Metopus (Protozoan) Movies

Metopus Video No. 1 - A metopus, ringed by a spiral fringe of beating cilia, exhibits its tumbling swimming style; under darkfield illumination at a magnification of 400x with a playing time of 23.8 seconds. Choose a playback format that matches your connection speed: 28.8k (modem), 56.6k (modem), or T1/Cable/DSL, or download this video clip in MPEG format (10.0 MB).

Unlike most other ciliates, which are aerobic, Metopus is anaerobic and lives in oxygen-depleted sediments. Some species have even been found living in sediments off the coast of Antarctica. In place of mitochondria, Metopus has respiratory organelles called hydrogenosomes.

Metopus belongs to the class Spirotrichea in the phylum Ciliophora; the ciliates, of which there are approximately 8,000 species, are generally considered to be the most evolved and complex of the protozoans. The cell surface is covered with hundreds of hairlike structures called cilia that are arranged in rows. The cilia beat in synchronized waves, propelling the organism through the water.